Conventionally, in a windshield wiper unit for wiping the front glass of a car, a system that activates a wiper arm by a link mechanism with a motor used as a drive source has been widely employed. As the function of the wiper system becomes more refined, a system that electrically controls a motor to thereby control the wiper movement has widely appeared in recent years in place of the above link drive system. In this motor control drive system, a configuration in which a control circuit and motor are integrated with each other is adopted in terms of product modulation or the like. For example, as disclosed in PCT Application Laid-open Publication No. 2002-511038, a motor is mounted in an automobile as a unit including a speed reduction mechanism.
In such a motor unit, however, a control circuit section is two-dimensionally arranged in a housing, and circuit components are two-dimensionally placed on the control circuit section, thereby increasing an area occupied by the mounted circuit components. Further, in the control circuit section, power system components such as a power MOSFET and relay, are all arranged on the printed wiring board, so that the width of a copper-foil pattern must be widened on the printed wiring board according to the current amount, correspondingly increasing the board size. It is desirable that the power system components be arranged on the large-sized printed wiring board in consideration of the heat radiation properties thereof. Even in view of this, the board size tends to be increased. Accordingly, the size of the control circuit section is likely to be increased for these reasons to thereby increase the size of the motor unit. The larger the size of the motor unit, the larger the size of the required mounting space for the unit to be provided on the automobile side becomes, and this problem does need to be solved.
An object of the present invention is to reduce the space occupied by the control circuit section in the motor unit to reduce the size of the entire motor unit.